def is_chinese(uchar):
    """判断一个unicode是否是汉字"""
    if uchar >= u'\u4e00' and uchar<=u'\u9fa5':
        return True
    else:
        return False

def is_number(uchar):
    """判断一个unicode是否是半角数字"""
    if uchar >= u'\u0030' and uchar<=u'\u0039':
        return True
    else:
        return False
    
def is_Qnumber(uchar):
    """判断一个unicode是否是全角数字"""
    if uchar >= u'\uff10' and uchar <= u'\uff19':
        return True
    else:
        return False

def is_alphabet(uchar):
    """判断一个unicode是否是半角英文字母"""
    if (uchar >= u'\u0041' and uchar <= u'\u005a') or (uchar >= u'\u0061' and uchar <= u'\u007a'):
        return True
    else:
        return False

def is_Qalphabet(uchar):
    """判断一个unicode是否是全角英文字母"""
    if (uchar >= u'\uff21' and uchar <= u'\uff3a') or (uchar >= u'\uff41' and uchar <= u'\uff5a'):
        return True
    else:
        return False

def is_other(uchar):
    """判断是否非汉字，数字和英文字符"""
    if not (is_chinese(uchar) or is_number(uchar) or is_alphabet(uchar)):
        return True
    else:
        return False
    
def Q2B(uchar):
    """单个字符 全角转半角"""
    inside_code = ord(uchar)
    if inside_code == 0x3000:
        inside_code = 0x0020
    else:
        inside_code -= 0xfee0
    if inside_code < 0x0020 or inside_code > 0x7e: #转完之后不是半角字符返回原来的字符
        return uchar
    return chr(inside_code)

def stringQ2B(ustring):
    """把字符串全角转半角"""
    return "".join([Q2B(uchar) for uchar in ustring])

def stringpartQ2B(ustring):
    """把字符串中数字和字母全角转半角"""
    return "".join([Q2B(uchar) if is_Qnumber(uchar) or is_Qalphabet(uchar) else uchar for uchar in ustring])


if __name__ == "__main__":
    print(stringQ2B('“'))